Thank you so much for the prompt response!
For some reason, it didn't work. I am explaining in more details what I did maybe it will help to pinpoint what I did wrong.
I downloaded the child theme and activated.
Then pasted the code you sent in the function file php
Then went to the page that has the basic recent posts element and added the following shortcode in a raw content element placed in the same section of page as "recent posts" :
[x_recent_posts count="2" show_excerpt="true"]